Jorgall cylinder-world

The site of the Battle of Iota Horologii was a Jorgall cylinder-world, a colony-ship, within the Iota Horologii system. It was not a planet and had no separate proper name.

Mortarion led the Death Guard aboard the vessel, together with a detachment of the Sisters of Silence, shortly before the Horus Heresy; no year is recorded for the action.